Luminaire



Aug. 24,192.6. l 1,597,185

W- A. DORY LUMINAIRE Filed Oct. 28, 1924 2 Sheets-Sheet 2 A INVENTOR I @www w17 :Y v M A'rroRNEY Patented Aug. 24, 19.26.

UNITED STATES PATENT OFFICE.

A'WILLIAIVI A. DOREY, OF NEWARK, OHIO, ASSIGNOR TOHOLOPHANE GLASS COMPANY, F NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

LUMINAIRE.

Application led October 28, 1924. Serial No. 746,272.

The object of the present invention is to secure a distribution of light elongated in the direction of the hallway so that units can be spaced widely apart without sacrificing uni- 5 formity and without wasting too much light on walls and corridor. I accomplish this by applying a special bowl arrangement to a bowl-type luminaire, in which a central area of the bowl is given an exact and defi- 1 0 nite limit or boundaries which will permit transmission of all light within the boundaries to be illuminated which can be obtained in that way without means for lateral deviation.

The problem in all corridor lighting is to have the luminaires close to the ceiling and to have a `fairly uniform brightness down through the corridor. v

To obtain this with a symmetrical distri bution of light around a vertical axis it is necessary to place an unusual number of luminaires close together on account of the fact that the corridors are relatively nar row, or else if few units are used, they must be spaced widely apart and the light must be thrown out at a wide angle so that a great proportion of it will be caught by the side walls instead of distributed in useful directions; moreover, if uniform illumination is secured on the floor of the corridor a succession of bright spots is usually found on the walls, a pair for each unit giving an uneven appearance.

Fig. l is a plan view of the interiorsurface of a refracting bowl employed in my invention shown in diagrammatic form, and

` Fig. 2 is a vertical cross section in the plane ,2-2 of Fig. l showing the interior only, also in diagrammatic form,

Figs. 8- and Il are diagrammatic views of a typical corridor showing the luminaires` in exaggerated scale. i i

Fig. 5 is a vertical cross section in a piane parallel to the hall, of a complete form of my device showing the relation between light source, reflector and bowl.

The various parts of the device are shown .in Fig. 5 which is a vertical cross section in the plane of the center line ofthe cor 50 ridor. 7 is the light source, and 8 isa refiector having on its outersurface double reflecting prisms, 9 is the lower bowl having horizontal refracting prisms l0 covering its exterior and adapted to transmit light reflected from the reflector and light received direct from thesource. The more distinctive part of the invention, the lower bowl, is shown in diagrammatic form in Figs. l and 2.

For the purpose of explaining the inven tion I have assumed a given set of conditions of mounting heights and width of corridor and determined the intercept of the various cones of light withl the dividing line between floor and walls. This intercept may then be translated to the surface of the prismatic bowl 9 by laying olf the angle of the arc useful in lighting the floor for each cone along the surface of the horizontal prism which delivers its light rays in that cone. These intercepts when translated to the bowl are shown in Figs. l and 2, as lines l-s'l, and l 3 4', which divide its surface into three sections, 6, 5, 6 which will be symmetrical to a straight line through the axis, parallel to the walls of the corridor. The central section 5 will be a strip extending across the whole surface of the bowl, and its area in proportion to the whole and also the contour of the intercepts will be determined very definitely by the installation conditions assumed, by the shape of the bowl and by the form of distribution of light in vertical planes from the horizontal prisms.

Line 2-2 in Fig. l divides the outer sections 6 and 6 into two halves which are provided with prisms deflecting the light oppositely. Each half section deflects the light toward the adjacent portion of the central section. i

If the interior of the refracting bowl be of smooth glass all of the light emitted by thecentralsection 5 as described above will .passdirect to the fioor of the corridor, within the line of division formed by the walls,

`and all of the light emitted by the two outward sections 6 and 6 will be transmitted to the side walls. In my construction I prefer to keep this central section smooth on the interior` or provided with very shallow radial flutesor roughened surfaces merely. giving suflicient spread to do away with sharp filament images. `In the two outer sections 6 and 6 I `use radial refracting prisms or fiutes designed to deviate the light laterally so that it will fall to a large degree within the limits of the floor or will strike right angles ,to thehall.

the side walls at points intermediate between two luminaires and thus promote uniformity of illumination of the side walls.

Figs. 3 and 4 are diagrammatic views of the corridoi' showing the luminaires in eX- aggerated scale, so as to show the' setting of the central section 5 and the Iouter section 6 and 6 with reference to the conditions of the installations.

Fig. 3 is a diagrammatic vertical cross section of a typical corridor in a plane at ll and Il are light rays issuing from the extreme boundaries ofthe area 5 and delivered at the junction between walls and floor. `Now if you consider any slanting cross section of -v the corridor the light rays emitted in that cross section from the boundaries of the area 5 will be delivered at the junction between walls and floor, the boundaries of area 5 having been shaped lto take care of y the change in angular relation between the limiting rays similar to l1 and l1.

Fig. l is a diagrammatic plan of' a portion of a corridor.v l2 and 12 are projections of the path of the light rays issuing from the eXtreme boundaries of the area 5 and delivered midway between units at the junction between wallsand floor. If these be extended they will pass through thecenter of the plan of the luminaire because they have not beensubject to lateral deiiection.

13 and 13 are projections of the path of typical light rays issuing from areas 6 and G and delivered at the same points as il and 1l. If these be extended they will not pass through the centre of the plan of the luminaire because they have been subjected to a lateral deflection. In general the area 5 lays down a light pattern substantially coincident with a unit portion of the floor havingits centre at the luminaire and the areas 6 and 6 deiiect the light rays laterally in thel direction of the longest dimension of this unit floor portion so as toincrease the light on the floor, soften the edges of the A light pattern and reduce the light on the walls directly opposite the units.

In other words, having been given an varea to be illuminated, at a prescribed mounting height and with a certain shape of bowl giving a definite distribution of' light, the contour between the plain and prismatic parts becomes absolutely xed. Theoretically, any change in (l) the width of the hall, (2) the mounting height, (3) .the vertical distribution of the unit or (Il)l the contour of the howl will involve some change in the shape of this central area. The prismatic radial areas are adjusted accordingly.

I have shown the unit as being entirely composed of'prismatic glass but it should be understood that any reflecting material can be Vemployed inthe upper portion and that the lower glass bowl may have deflecting areas of any character abutting a coinparatively translucent area for the purpose herein speoilied.

While I have shown and described the invention with reference to corridor lighting, the form of construction is equally useful in street lighting installations and similar service, the walls of the houses and street taking the place of the walls and floor. of the corridor, and in these installations it may be found desirable to use double glassware in which the prismatic construction is entirely contained between covers smooth on the outside and inside.

I claim:

l. A luminaire for corridorlighting comprising a light source, and bowl forming a unit enclosing the source, the bowl having a central area with its major axis paralleling the side walls of the corridor and com iaratively denser adjacent areas.

2. A luminaire for corridor lighting .comprising a light source, a reflector and bowl forming a unit enclosing the source?,` the bowl having a central area with its major axis paralleling the side walls of the corridor and comparatively denser, adjacent areas. Y

A luminaire for corridor lighting, comprisino' a light source, a reHect'or and bowl forming-a unit enclosing the source, the bowl having a central area with its major axis paralleling the side walls of the corridor and adjacent areas adapted to direct light rays to the floor within thelimits Iof l the side walls.

4. A luminaire for corridor lighting coinprising a light source, a reflectorand bowl forming a unit enclosing the source, the bowl having a comparatively non-deflecting central area with its major axis paralleling the side walls of the corridor and adjacent areas adapted to direct light rays towards the floor within the limits of the side walls.

5. A luminaire for corridor lightinglcoim prising a light source, a reflector and bowl forming a unit enclosing the source, the bowl having a translucent central'area with its majorV axisl paralleling the side walls of the corridor and comparatively denser adjacent areas adapted to direct light rays provided with radial refracting corrugations adapted to direct light rays towards the ,floor within the limits of the side walls. o Y

Y, 7, A luminaire for corridor lighting comprising a light source, a refiector and bowl forming a unit enclosing the source, the

lil

bowl having on its interior surface a comparatively non-detlecting central area with its major axis paralleling the side Walls of the corridor and adjacent areas provided with radial refracting corrugations adapted to direct light rays towards the floor within the limits of the side walls.

8. A luminaire for corridor lighting comprising a light source, a reflector and bowl forming a unit enclosing the source, the reflector having double reiiecting prisms on its outer surface, and the bowl having on its inm terior surface a central area within its major axis paralleling the side walls of the corridor and adjacent areas provided on their inner surfaces with radial retracting corruga tions adapted to direct light rays towards the iioor within the limits ot the side walls.

9. A luminaire tor corridor lighting comprising a light source, and a bowl enclosing the source, the bowl having a comparatively non-detlecting central area with its major axis paralleling the side walls of the corridor and adjacent areas provided with radial refracting corrugations, the plain area being limited to that portion of the surface adapted to emit light rays to the floor of the corridor within the limits et the side walls and the corrugated areas being adapted to deflect light rays laterally towards the floor.

l0. A luminaire for corridor lighting comprising a light source, and a bowl enclosing the source, the bowl having on its interior surface a comparativelyY non-deflecting cen tral area with its major axis paralleling the side walls of the corridor and adjacent areas provided with radial retracting corrugations, the plain area being limited to that portion of the surface adapted to emit light rays to the floor of the corridor within the limits of the side walls and the corrugated areas being adapted to deiiect light rays laterally towards the Hoor.

l1. A luminaire for corridor lighting comprising a light source7 a reiiector andvbowl ltorming a unit enclosing the source, the bowl having on its interior surface a comparative ly non-deflecting central area with its major 1 axis paralleling the side walls of the corridor and adjacent areas provided with radial refracting corrugations, the plain area heilig limited to that portion of the surface adapted to emit light rays to the floor oi the corridoi' within the limits of the side walls and the corrugated areas being adapted to deflect light rays laterallyT towards the floor.

l2. A luminaire for corridor lighting comprising a light source, a reflector and bowl forming a unit enclosing the source, the bowl having a. central area with its major axis paralleling the side walls ot the corridor and adjacent areas provided with radial refracting corrugations, the central area being limited to that portion of the surface adapted to emit light rays to the floor-'of the corridor within the limits of the side walls and the corrugated areas being adapted to deflect light rays laterally towards the floor.

13. A luminaire for Corridor lighting comprising a light source, a reflector having double reflecting prisms on its outer surface and a bowl forming a unit enclosing the source, the bowl having a central area with its major axis paralleling the side walls of the corridor and adjacent areas provided with radial refracting corrugations, the central area being limited to that portion of the surface adapted to emit light rays to the floor of the corridor within the limits oi' the side Walls and the corrugated areas being adaptd to deflect light rays laterally towards the oor.

Signed at New York, in the county of New York and State of New York, this 27 th day of October 1924.

VILLIAM A. DOREY. 

